Conflict Outcome in Male Green Swordtail Fish Dyads (Xiphophorus Helleri): Interaction of Body Size, Prior Dominance/Subordination Experience, and Prior Residency

Abstract

This work was funded by an operating grant from the NSERC of Canada to JPB. SummaryThe relative contribution of asymmetries in prior experience, size, and prior residency to the determination of dyadic dominance between unacquainted individuals was examined using pairs of green swordtail fish, Xiphophorus helleri. Four types of encounters were staged between an intruder and a smaller resident: (1) both had experienced prior victory; (2) both had experienced prior defeat; (3) the intruder had experienced prior victory and the resident prior defeat; and (4) the intruder had experienced prior defeat and the resident prior victory. In a fifth condition in which two intruders met, one was a prior subordinate and the other a prior dominant smaller in size than its opponent. In all these encounters, the superiority in lateral surface of one fish varied between 0 to 30% over that of its opponent. Results showed that (1) when size differences between contestants were within the range of 0-10% and there was an asymmetry in prior social experience, conflicts were essentially resolved according to prior experience with prior winners systematically defeating prior losers; (2) prior residency of 3 hours was an advantage only when both opponents had experienced prior defeat before meeting and when size asymmetries were small (e.g. <20%). It was not an advantage between prior winners or between a prior winner and a prior loser; (3) when large size asymmetries existed (e.g. 20-30%), size uniquely determined dominance outcome and nullified other advantages or disadvantages due to prior social experience and prior residency; and (4) at intermediate levels of size asymmetries (e.g. 10-20%), size partially cancelled any advantage due to a prior victory, and gradually beacme the most important factor in accounting for victories.

Dominance and growth of Diplodus sargus (Pisces: Sparidae) in small captive groups

“…The role of size in the organization of agonistic interactions has been documented for a wide variety of fish (Abbott et al, 1985;Beaugrand et al, 1996). However, our results showed no relationship between initial size and dominance.…”

The role of hen's weight and recent experience on dyadic conflict outcome

“…Previous experiences of victory or defeat, 3-hour familiarity with the meeting place, and size differences were found to predict the dominant subjects in unacquainted pairs. Moreover, results obtained by Beaugrand et al ( , 1996 clearly suggest that previous victory or defeat experience and size can either add or cancel out each other. Though Xiphophorus fish and Gallus are phylogenetically distant, it may be hypothesised that they share not only a common basic dominance mechanism, but also some determining factors as well, namely recent experience, familiarity with the surrounding, and size or weight.…”

“…Frey and Miller (1972), Beaugrand and Zayan (1985), Beacham (1988 simultaneously varied many parameters to establish their combined effects. Experiments by Beaugrand and Zayan (1985) and Beaugrand et al ( , 1996 have investigated in Xiphophorus helleri the interactions of several factors in dyadic dominance encounters. Previous experiences of victory or defeat, 3-hour familiarity with the meeting place, and size differences were found to predict the dominant subjects in unacquainted pairs.…”

Aggression and dominance in cichlids in resident-intruder tests: the role of environmental enrichment

“…individuals that are familiar with, and have invested in, a territory or environment] have a greater likelihood to dominate intruders or newcomers [i.e. individuals that are unfamiliar with a territory or environment upon meeting the resident] than vice versa (Braddock, 1949;Thinès & Heuts, 1968;Heuts, 1979;Beaugrand et al, 1991Beaugrand et al, , 1996Heuts & Nijman, 1998). It stems from a pay-off asymmetry between residents and intruders.…”